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Discussion Starter · #1 ·
Hey guys. Can anyone give me a starting point for Hoosiers on my brand new 240 Cup car. I'm having troulbe putting 1 second on my Elise and this car should be much faster. Track is Catalunya school circuit (forza 4) :) thx
 

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I try to estimate how much they are going to warm up during the next session (I'm assuming you're doing HPDE). I aim for 26/29 F/R hot. The warmer the day and the longer the session, the less starting air pressure. Also, how hard they are going to be driven and the nature of the track (long fast sweeper?) is a factor.

But say it's a 75 degree day for a 30 minute stint, something like 3 lbs off each tire.

Just measure em right after coming in. This will help to estimate the next time.

Fine tuning, on a track clockwise the left tires will build more heat/pressure.

On a warm day you might be surprised how much air you let out over the day.

Oops! Just noticed it's a virtual situation. Please let us know what you decide!
 

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I kept myself busy with tire-pressure calculation , in the beginning with the Official European formula , but later my own calculation, because its better.

So if you give me exact data of tires and car , I can calculate the lowest save pressure for the tires, above wich you can play higher for beter handling and to influence under- and over-steer.
For races some colateral damage is accepted, so lower pressure can even do.

Even made a spreadsheet to determine what pressure to fill cold for special conditions ( for instance racing where the tire inside air can get 190dgrF so I read once) to get a warm pressure wich gives the tire the deflection that is save. Also calculation of pressure but with the old official formula wich is OK for standardload/P-tires and XL/reinforced/Extraload.


Need from car the weights on seperate wheels , 2nd best axles, 3th best empty weight and way you load it and if motor is in front or back.

From tires maximum load or loadindex, and kind of tire to determine the pressure needed for that /reference-pressure Pr. This is not the maximum pressure.
Also sises and speedcode of tires.

If you want to play with it yourselves , here the link to my Motorhome-tire pressure calculator map on my One-drive ( former Skydrive) that belongs to my hotmail.com adress with same username as in this forum.
In that map the motorhome calculator ,wich can be used with some adaption for other cars too, but also the pressurecalculationwithtemp, for to play with the temperature and pressures.

https://onedrive.live.com/?cid=a526e0eee092e6dc#cid=A526E0EEE092E6DC&id=A526E0EEE092E6DC%21793

to use a spreadsheet first download it to your computer by RIGHT-CLICKING and then choose DOWNLOAD.
Dont use leftclicking or open in Web-App or Excell when rightclicked , goes wrong or to complicated.
After download and eventual virus-check, open it in Excell Programm on your computer , but Open Office Calc can handle it too.
 

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Discussion Starter · #4 ·
Thanks guy. 26/29 hot is not far from my R tires. I thought slicks ran a lot lower. I will plug those in, probably starting abt 23/26 cold. I read that there is tire temp telemetry somewhere in the game so I'll find it and look at hot actual temps. Thx again.
 
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